7. Which of the following statements is correct for both a monopolist and a perfectly competitive firm? i. The firm maximizes profits by equating marginal revenue with marginal cost. ii. The firm maximizes profits by equating price with marginal cost. iii. Demand equals marginal revenue. iv. Average revenue equals price. (A) i), iii), and iv) only (B) i) and iv) only (C) i), ii), and iv) only (D) i), ii), iii), and iv)